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Homepage Archive - January 2023 (page 1)

See Page 1 | 2 | 3 | 4 | 5 of the January 2023 homepage archives.
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Friday the 6th

Railroad Radio

Railroad Radio, August 1960 Electronics World - RF CafeRailroads have played a fairly major role in communications development. Beginning with carrying letter mail as cargo across vast distances much more quickly than horse-drawn coaches and even Pony Express, much of the early telegraph and then telephone electric lines were strung along rail lines. Doing so facilitated initial installation as well as maintenance since materials and personnel could be delivered quickly and conveniently. Many miles of old telegraph lines can still be seen lurking in the trees and weeds along tracks all over the country. Both telegraph and wireless communications were used to keep in contact with trains to establish location, weather condition, equipment status, indian uprisings, to enable messaging to and from passengers, and to provide navigation instructions when the need arose. The world's first mobile radio broadcast took place on a train. This 1960 "Railroad Radio" article in Electronics World magazine reported on the state of the art at the time...

Multi-Dimensional Wide-Bandgap Power Devices

Multi-Dimensional Wide-Bandgap Power Devices - RF Cafe"Three researchers based in the USA and the UK have reviewed the potential for applying multi-dimensional (multi-D) power device architectures with a view to suggesting more appropriate figures of merit (FOMs) compared with those applied to essentially 1D structures. Such FOMs are key to assessing the performance limits and scaling capabilities of power devices. The authors - Yuhao Zhang of Virginia Polytechnic Institute and State University (Virginia Tech), Florin Udrea of the University of Cambridge, and Han Wang of the University of Southern California - focus on multi-D structures pioneered in silicon in an effort to beat off the competition from potentially higher-power-capable but more expensive materials such as silicon carbide (SiC) and gallium nitride (GaN): superjunctions (SJs), multi-channels, fin field-effect transistor (FET), and trigate..."

Research at the Threshold of Space

Research at the Threshold of Space, May 1957 Radio & TV News - RF CafeAtmospheric scientists suspected as recently as early 1957 that Earth's upper atmosphere (ionosphere and beyond) temperature might be around 1,000 °K. I say "suspected" because we had not yet launched instruments there to make actual measurements. Soundly posited and agreed upon theory was validated a short time later when sounding rockets reliably reported a maximum of about 1,300 °K in the upper ionosphere. We did not know for sure what electromagnetic wavelengths and their respective energy densities would be outside the protective layers of gases encompassing Earth. Much more was known about the depths of the planet's oceans than of its atmosphere. Scientists knew that life was abundant below the water's surface but did not know what, if any, life existed at altitudes any greater than the tallest mountain. Outer space, devoid of everything we consider essential to support life as we know it, would be a hostile environment for humans or even electronic instrumentation. It is always interesting to recall that while you only need to dive 33 feet below the water's surface to double the ambient pressure, you need to go 18,000 into the atmosphere to halve the pressure. Beginning in 1957...

Memristors Run AI Tasks at 1/800th Power

Memristors Run AI Tasks at 1/800th Power - RF CafeHere's another news tidbit to tweak the idiot who keeps harassing me for daring to claim memristors are real entities. "These brain-mimicking devices boast tiny energy budgets and hardened circuits. Memristive devices that mimic neuron-connecting synapses could serve as the hardware for neural networks that copy the way the brain learns. Now two new studies may help solve key problems these components face not just with yields and reliability, but with finding applications beyond neural nets. Memristors, or memory resistors, are essentially switches that can remember which electric state they were toggled to after their power is turned off. Scientists worldwide aim to use memristors and similar components to build electronics that, like neurons, can both compute and store data. Such brain-inspired neuromorphic hardware may also prove ideal for implementing neural networks - AI systems increasingly finding use in applications such as analyzing medical scans and empowering autonomous vehicles. However, current memristive devices typically rely on emerging technologies with low production yields and unreliable electronic performance..."

The Novice 90 Antenna

The Novice 90 Antenna, October 1959 Popular Electronics - RF CafeDo you know what a Fahnestock clip is? Chances are you would know one if you saw one, but you never knew what it was called. This 1969 Popular Electronics magazine article, requested by RF Cafe visitor Jan C., references a Fahnestock clip in the parts list for constructing an easily tunable long-wire antenna. The simple circuit uses just a handful of components for matching the high impedance antenna to a relatively low impedance coaxial cable feeder. A flashlight bulb and a few turns of wire act as an RF sniffer to tune for best match. A high quality ground is essential to the setup's operation so the author describes using copper sulphate crystals or rock salt to treat the ground rod vicinity for better conduction. It's a short article so go ahead and read it - if for no other reason than to see what a Fahnestock clip is...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Thanks Once Again to everythingRF for Long-Time Support!

everything RF Searchable Database - RF CafePlease take a few moments to visit the everythingRF website to see how they can assist you with your project. everythingRF is a product discovery platform for RF and microwave products and services. They currently have 267,269 products from more than 1397 companies across 314 categories in their database and enable engineers to search for them using their customized parametric search tool. Amplifiers, test equipment, power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers, power supplies, and everything else. Please visit everythingRF today to see how they can help you.

Thursday the 5th

Carl & Jerry: Operation Startled Starling

Carl & Jerry: Operation Startled Starling, January 1955 Popular Electronics - RF CafeThanks once again to Mr. Ferrous Steinke, quite the Carl & Jerry fan, for providing the following content regarding the technodrama entitled "Operation Startled Starling," from the January 1955 issue of Popular Electronics magazine. "Biosonics as a repelling technique are based on acoustical signals emitted by birds and other animals to convey information to conspecifics. Two audible bird warning stimuli, distress and alarm calls, have been explored and/or used for acoustically repelling birds from urban and rural roosts, fish-rearing ponds, airport runways , agricultural settings, and other locations. Distress calls are those emitted by birds when being restrained, attacked by a predator, or subjected to other types of severe conditions, whereas alarm or warning calls are usually given in response to the presence of an intruder or predator. Depending on the species and situation, these warning calls often cause conspecifics, and sometimes closely related species, to leave the immediate area. The use of natural communication signals to frighten birds has received considerable attention in the past several decades for managing certain pest birds. They have the advantage of being more effective...

The Memristor - A Reality

The Memristor - RF CafeThe term memristor - a portmanteau of "memory" and "resistor" - is the fourth fundamental electronic component, along with the resistor, capacitor, and inductor. The name was coined in 1971, which sounds like yesterday to someone like me (born in 1958), but incredibly that is now half a century ago. Until fairly recently, the memristor was merely a theoretical curiosity existing in academic papers. In April of 2008, HP Labs (Hewlett-Packard) reported on successfully building a nanoscale memristor in their R&D lab. As with all new technologies, since that time much progress has been made. This conceptual diagram illustrates the symmetry of the four basic circuit components - the resistor, the capacitor, the inductor, and the memristor. Per Wikipedia: "Chua in his 1971 paper identified a theoretical symmetry between the non-linear resistor (voltage vs. current), non-linear capacitor (voltage vs. charge), and non-linear inductor (magnetic flux linkage vs. current)...

A New Look at Positive Current Feedback

A New Look at Positive Current Feedback, November 1957 Radio & TV News - RF Cafe"The term, positive current feedback, is disturbing to some because, as is well known, positive feedback increases the distortion of an amplifier to which it is applied. This is true in this application also, but it must be noted that the net feedback applied to the amplifier is never positive but simply less negative in the region where the positive current feedback is effective." Wow, that is a lot like what politicians refer to a "baseline budgeting." When one political party says it is going to "cut the budget," while the other complains that doing so will "starve children" and "hurt women," what it really means is that spending will not be increased this time as much as what had originally been planned, although it will actually be higher than the last time. We know the government never actually spends less money one year than it did the year before, but there are a lot of "low information" people who never suspect a thing - just keep the welfare checks and food stamps flowing...

Longwave Infrared Microresonators in Native Germanium

Longwave Infrared Microresonators in Native Germanium - RF Cafe"What if there were a gadget that could within short order check whether you have COVID or the flu - or maybe it would even pick up that you have diabetes without knowing it? The device could figure all this out without you having to go to a doctor or a laboratory. This technology could become a reality within a few years, and electrical engineers are some of people who make it possible to create such gadgets, which contain a key component called the whispering gallery mode microresonator. New technology is providing better optical sensors, which are important for electronics, including devices that analyze chemicals using light. 'We've built the lowest loss whispering gallery mode microresonator out there for the longwave infrared spectrum. Because the longwave infrared spectrum provides definitive information about chemicals..."

Meter Movements

Meter Movements, September 1960, Popular Electronics - RF CafeMechanical meter movements have been around since the late 1800s. In 1882 Jacques-Arsène d'Arsonval and Marcel Deprez developed a meter movement with a stationary permanent magnet and a moving coil of wire which survives today as the dominant form. Lord Kelvin's (aka William Thompson) galvanometer preceded d'Arsonval's by a decade or so, but it relied on the Earth's magnetic field and needed to be properly oriented to work. d'Arsonval's movement incorporated a permanent magnet instead to improve sensitivity and convenience. I'm not sure d'Arsonval gets sole billing on the name - why not the Deprez movement? This article in Popular Electronics magazine from 1960 is as relevant today as it was more than half a century ago...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Thanks to Wireless Telecom Group for Their Support!

Wireless Telecom Group (RF power and noise measurement) - RF CafeThe Wireless Telecom Group, comprised of Boonton, Holzworth, and Noisecom, is a global designer and manufacturer of advanced RF and microwave components, modules, systems, and instruments. Serving the wireless, telecommunication, satellite, military, aerospace, semiconductor and medical industries, Wireless Telecom Group products enable innovation across a wide range of traditional and emerging wireless technologies. A unique set of high-performance products including peak power meters, signal generators, phase noise analyzers, signal processing modules, 5G and LTE PHY/stack software, noise sources, and programmable noise generators.

Wednesday the 4th

Radio Aids to Aircraft Navigation: Ranges & Direction Finding

Radio Aids to Aircraft Navigation: Low-Frequency Ranges & Direction Finding, July 1960 Electronics World - RF CafeFrom the time the Wright brothers made their historic 1903 flight at Kill Devil Hills on the coast of North Carolina, aviation progressed at a geometric rate. For safety, convenience, and commercial reasons, navigation methods and equipment necessarily developed alongside aircraft advances. Both realms required a huge amount of innovation, research, and development. All first-world countries participated in the effort in order to establish and/or maintain leadership in particular realms of the science. One of the earliest navigational aids was the creation of detailed maps with easily recognized landmarks, and placement of flags and windsocks where they would be easily visible from an airborne vantage point. That facilitated more accurate "dead reckoning" navigation. Bonfires were built in specific locations for the benefit of night flyers. Next came electronic navigational equipment like direction finding (zeroing in on a commercial radio broadcast tower), omnidirectional (VOR and VORTAC) broadcast for flying bearing relative to fixed stations broadcasting compass information...

Anatech Electronics Intros 3 Filter Models

Anatech Electronics Intros 3 Filter Models for January 2023 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new filter models have been introduced - a 925.3 - 938.3 MHz cavity bandpass filter with 1.5 dB insertion loss, a 988.5 MHz cavity bandpass filter with 45 MHz bandwidth and 1.8 dB insertion loss, and a 1730 MHz cavity bandpass filter with a 32 MHz bandwidth and 2.5 dB insertion loss. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found, or the requirements are such that a custom approach is necessary...

McWatts Comic Strip

McWatts Comic Strip, January 1957 Popular Electronics - RF Cafe"McWatts" was an electronics-themed comic that appeared in Popular Electronics magazine back in the late 1957's. Artist Carl Kohler's main character is a stereotypical Joe Sixpack type electronics hobbyist who always dreams up unique ways to deal with situations. This edition shows McWatts' way of keeping the kids from using his prized tools as toys. My father would appreciate this if he had read Popular Electronics back in the day. I was always leaving my poor father's tools laying around the house and too often in the yard where they would get rained on and start to rust. If I were him, I would have been harder on me for repeat offenses. Carl was also the creator of the very popular series of humorous stories about an electronics-obsessed husband and his barely tolerating wife...

Zig-Zag Lightning Mediated by Metastable Oxygen

Zig-Zag Lightning Mediated by Metastable Oxygen - RF Cafe"Lightning flashes have distinctive zig-zag shapes and physicists have long wondered why. Now, John Lowke and Endre Szili at the University of South Australia have done calculations that could explain this behaviour. The duo created a model that describes the unusual propagation of 'lightning leaders' - channels of ionized air - that connect thunderclouds to the ground. They propose that the zig-zag steps are associated with highly excited, metastable oxygen atoms - which make it far easier for electrical current to flow through the air. Lightning appears to propagate in a series of steps that involve leaders, which are tens of metres long and originate from thunderclouds. A leader will light up for about 1 µs as current flows, creating a step. Then the channel will darken for tens of microseconds, followed by the formation of the next luminous step at the end of the previous leader – sometimes with branching occurring. This process repeats to create a familiar jagged lightning-bolt shape..."

Reception of Single-Sideband Signals

The Reception of Single-Sideband Signals, November 1952 QST - RF CafeEven though the concept could easily be demonstrated to be viable mathematically, single sideband operation was early on widely regarded as an unrealizable laboratory curiosity, especially with a suppressed carrier. More circuitry is of course needed to accomplish single sideband communications both on the transmit and receive sides, but other than stricter stabilities and precision for frequency sources, single sideband operation is easily obtainable. Similar to back when this 1952 issue of QST published "The Reception of Single-Sideband Signals," there still remains today a debate over whether voice quality is as good versus double sideband, but there is no arguing whether the spectral efficiency gained with single sideband is a great benefit to the world. My first experience with single sideband, suppressed carrier operation was while designing a modem for an Inmarsat base station installation in Connecticut. At the time, there were no ICs available to do the job, so individual components were used for the mixers, oscillators, and quadrature power splitters/combiners. A potentiometer was used on the I channel (in-phase) to null out the carrier. Nowadays, a single IC does the entire job, including often with an integrated filter...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 12,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Tuesday the 3rd

Computer Memory Devices - Part 2

Computer Memory Devices, August 1960 Electronics World - RF CafeThe first installment of this two-part "Computer Memory Devices" series discussed the use of magnetic data storage in the form of drums and tapes. Both types provide long-term, non-volatile storage, but both suffer from a relatively slow execution of writing and reading to and from, respectively, the media. In 1960 when Electronics World magazine printed the articles, drums and tape were used during execution of programs because electronic storage in the form of vacuum tube circuits was extremely costly in terms of power, cost, and physical space. As recently as the early 1980's, magnetic tape storage still dominated the data storage field, especially where huge amounts on information needed to be stored and retrieved. Semiconductor memory, while less voluminous and less power hungry, still added a lot to the cost of computers. If you were around at the time and used a PC, you remember that 64 kilobytes or RAM...

Windfreak Blog: The Ins and Out of Radio Frequency

Windfreak Blog: The Ins and Out of Radio Frequency - RF CafeDavid Goins, founder of and chief engineer for Windfreak Technologies, has written a number of application notes pertaining to the specification and testing of RF and microwave frequency signal generators. "The Ins and Outs of Radio Frequency" is addressed to people not familiar with the concept of electromagnetic radiation, and uses a very nicely designed infographic format to augment the brief textual discussion. It is a great classroom prop for introducing middle and high school students to radio. "Radio frequencies are used in a wide range of items, but most people do not understand how they work or are used in our daily lives. A radio frequency is a type of electromagnetic energy and is measured in hertz, and it is used by radars, radios, televisions, microwaves, GPS, cells phones, and satellites. When you are buying these types of products, you should look for items that come with warranties, are high in quality..."

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments. 50 Ω and 75 Ω models are available, along with a full line of precision calibration and connector adaptors.

Mac's Radio Service Shop: Barney and the Boosters

Mac's Radio Service Shop: Barney and the Boosters, June 1949 Radio & Television News - RF CafeAs one who recently installed an outdoor antenna with a signal booster on it, I definitely considered whether my exercise and investment would be worthwhile because all the preamplification in the world wouldn't help if the signal-to-noise ratio was lousy to begin with. This statement in Radio & Television News magazine from Mac McGregor, proprietor of Mac's Radio Service Shop, sums it up well, "One thing you have to remember is that the booster has to have something to boost. Unless the antenna can deliver some sort of signal to it, it has nothing to work on. The results are about the same as when a small boy reaches the bottom of his soda. He keeps on trying, but about all his straw delivers is noise..."

Tunnel Magnetoresistance at Room Temperature

Tunnel Magnetoresistance at Room Temperature - RF Cafe"Magnetic tunnel junctions (MTJs), which consist of two ferromagnets separated by a non-magnetic barrier material, are found in a host of technologies, including magnetic random-access memories in computer hard disk drives as well as magnetic sensors, logic devices and electrodes in spintronic devices. They do have a major drawback, though, which is that they do not operate well when miniaturized to below 20 nm. Researchers in China have now pushed this limit by developing a van der Waals MTJ based on a semiconducting tungsten diselenide (WSe2) spacer layer less than 10 nm thick, sandwiched between two ferromagnetic iron gallium telluride (Fe3GaTe2) electrodes. The new device also has a large tunnel magnetoresistance (TMR) at 300 K, making it suitable for memory applications..."

Frenzied Radio

Frenzied Radio, February 1930 Radio-Craft - RF Cafe"And there is nothing new under the sun." - Ecclesiastes 1:9, NKJV (did you know this is the origin of the saying?). This 1930 editorial by Radio-Craft editor Hugo Gernsback describes a coordinated scam perpetrated by radio manufacturers to compel consumers to buy new sets rather than have their existing sets repaired; such schemes persist today. In short, retail prices were inflated to accommodate a built-in "trade-in" allowance that far exceeded the repair cost or used radio cost. Radio service shops were getting the short shrift because many people who might have otherwise elected to have repairs made would instead trade in the old set for a new one. That a conspiracy was underfoot was evidenced both by the practice of destroying traded-in sets so they cannot be used again (similar to the Cash for Clunkers program where engines were destroyed after trade-in), and by making it difficult or even impossible for repair shops to obtain adequate technical documentation. The latter is a prime reason why magazines like Radio-Craft began publishing Radio Service Data Sheets monthly...

Many Thanks to KR Electronics for Long-Time Support!

KR ElectronicsKR Electronics has been designing and manufacturing custom filters for military and commercial radio, radar, medical, and communications since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop, equalizer, duplexer, diplexer, and individually synthesized filters for special applications - both commercial and military. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications. All common connector types and package form factors are available. Please visit their website today to see how they might be of assistance. Products are designed and manufactured in the USA.

Monday the 2nd

Computer Memory Devices

Computer Memory Devices, July 1960 Electronics World - RF CafeIn 1960 when this "Computer Memory Devices" article appeared in Electronics World magazine, digital electronic computers were still a relatively new technology. Although bulky and power-hungry, accomplishing digital manipulations of data for logic, mathematics, sorting, etc., was relatively easy, but unless programming instructions were fixed and output was used real-time, an ability to store data is necessary. Memory banks composed of vacuum tubes could -and often did - do the job, but the data was neither permanent nor physically transportable. If power is lost, the information is lost. We still suffer that issue even today volatile type memory. For more permanent data storage, magnetic media was developed, solving both aforementioned down sides...

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments. 50 Ω and 75 Ω models are available, along with a full line of precision calibration and connector adaptors.

The Filamentless Tube

And Now - The Filamentless Tube, March 1933 Radio-Craft - RF CafeIf this article had appeared in an April edition of Radio-Craft magazine, I might have suspected it was a Fool's hoax, but it was the March 1933 issue and, it turns out, it was serious. Obviously the "filamentless tube" concept did not work out well since the overwhelming majority of vacuum tubes sold up until the time semiconductors took over the electronic device market had separate filaments (heaters). It was a great idea, though, and the world is thankful for the pioneers who take the figurative "arrows" for the rest of us. We benefit from their hard work and ingenuity, while they suffer the agony of defeat, with an occasional taste of the thrill of victory (ref. ABC's Wide World of Sports). It is too bad the concept did not work because, as pointed out in the article, the benefits of simpler, cheaper manufacturing and greatly extended tube lifetime would have been a significant asset to the electronics industry...

Radio.com Domain up for Auction

Radio.com Domain up for Auction - RF CafeDo you remember back in the mid to late 1990's when the World Wide Web (WWW) was just becoming a major "thing," and people were buying up domain names in hopes of selling them later at astronomically high prices? Back in those days there was no restriction on which domain name you could claim, even if it was the name of a major company. Not every corporate honcho was convinced that a time would come when having a website bearing the company name would be essential. Not having someone else own it would be equally essential. I read of cases where McDonalds and one of the auto makers paid big $$$ to buy domain names from Joe Sixpack types with more foresight. Domain names like radio.com, travel.com and realtor.com were fetching enviable prices as well. At the moment the Radio.com domain name is up for auction. The starting bid is $2.5 million. Here's your chance...

Russian Jamming: The Electronic Iron Curtain

Russian Jamming: The Electronic Iron Curtain, April 1959 Popular Electronics - RF CafeWhoa! Take a look at the RF feedthrough and lightning arresting choke on the feed line on the original Voice of America transmitter in Munich, Germany. Now that is serious stuff. This story from a 1959 issue of Popular Electronics reports on the extreme lengths to which the Soviet bloc went in order to prevent its countrymen from hearing radio signals broadcast by the Voice of America and other non-state-approved beacons. Quarter megawatt transmitters sent messages of freedom that could be picked up by even the most remote crystal sets that didn't have the advantage of amplification. Ground-wave, sky-wave, and short-wave jamming techniques were employed to ensure the only signal that could be received was a buzz-saw type noise. Not so long ago, and certainly in 1959, America was viewed as a beacon of freedom, both figuratively via word-of-mouth and underground newspapers, and literally via high powered radio broadcasts directed into cordoned off countries ruled by Communist rulers. Herculean efforts were made by the likes of Stalin, Khrushchev, Castro, Kim Il-sung, Pol Pot, and various other despots to prevent any form of communications with the outside world. I remember back when my grade school classmates and I were practicing hiding under our desks in the event of a nuclear bomb attack...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Please Thank Lotus Communication Systems for Their Support!

Lotus Communication Systems Modular RF/Microwave Components - RF CafeLotus Communication Systems began in 2009, setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex Country, Massachusetts. Lotus is committed to highest quality and innovative products. Each RF/microwave module meets exceedingly high standards of quality, performance and excellent value, and are 100% MADE IN USA. Lotus' RF/microwave products cover frequency band up to 67 GHz. Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production. All products are custom designed. We will find a solution and save your time and cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters.

Sunday the 1st

Electronics Themed Crossword for January 1st

Electronics Theme Crossword Puzzle for January 1st, 2023 - RF CafeThis custom made Electronics theme crossword puzzle for January 1st is provided compliments of RF Cafe. A special message is included (marked with asterisk *). All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. As always, this crossword puzzle contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to ISOTEC for Continued Support!

ISOTEC Corporation - RF CafeSince 1996, ISOTEC has designed, developed and manufactured an extensive line of RF/microwave connectors, between-series adapters, RF components and filters for wireless service providers including non-magnetic connectors for quantum computing and MRI equipments etc. ISOTEC's product line includes low-PIM RF connectors components such as power dividers and directional couplers. Off-the-shelf and customized products up to 40 GHz and our low-PIM products can meet -160 dBc with 2 tones and 20 W test. Quick prototyping, advanced in-house testing and high-performance. Designs that are cost effective practical and repeatable.

 

   

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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com